In snowmobile design, lightness of weight is essential. In order to reduce the weight of snowmobiles, manufacturers are constantly attempting to simplify the operations of snowmobiles and shrink the size of parts. In modern snowmobiles, the operation of the endless track system, which interfaces with the snow, has been greatly simplified through the use of slide rails to support the track. A typical modern endless track system includes a wide loop of track, which may have ridges formed on the outer surface thereof to increase traction with the snow. The track extends around a drive wheel, driven by an engine. The track likewise surrounds two parallel slide rails, which may each have one or more idler wheels at one or both of its ends. A suspension may couple the slide rails to the body of the snowmobile to absorb shocks from uneven terrain.
The slide rails provide a simple lightweight structure for maintaining a large portion of the track parallel to the ground in a position to engage the snow. During operation, the track slides over the rails, creating a great deal of heat and friction losses. To reduce friction, the lower surface of the slide rails bear strips of material, referred to as Hyfax, formed of a low-friction material. In typical applications the hyfax is formed of an ultra-high molecular weight (UHMW) polymer. Series of metal clips secured along the interior surface of the track engage the Hyfax to provide a low friction interface.
Although the Hyfax and track clips are designed to reduce friction as much as possible, friction is nonetheless present along with the heat it generates. In some snow conditions, snow from the environment will melt on the Hyfax, providing both cooling and lubrication. In very cold conditions, the snow may contact the Hyfax, but not melt to provide a lubricant. In addition, in very fine, dry snow and on ice, such as frozen lakes and well traveled trails, an insufficient volume of snow will contact the Hyfax. Heat will therefore build up in the Hyfax. When the UHMW polymer constituting the Hyfax reaches 180° to 212° F., it begins to break down. It may become distorted and soften, causing the track clips to start sticking to the sliders, increasing both friction and wear. At temperatures at or above 267° F., the Hyfax will melt.
The weight of snowmobiles is also reduced by using a small radiator that takes advantage of surrounding snow for cooling, rather than relying solely on air as in most other types of vehicles. A typical radiator mounts above the track, beneath the seat of the snowmobile. In some conditions, the track will throw snow onto the radiator. However, as with the Hyfax, on ice and in fine, dry snow, the volume of snow contacting the radiator may be insufficient to provide adequate cooling.
In view of the foregoing, it would be an advancement in the art to provide a more effective system for cooling the Hyfax and radiator of a snowmobile. Such a system should improve cooling regardless of snow conditions and be both inexpensive and lightweight. It would be a further advantage to provide an improved cooling system that could be incorporated into an existing endless track drive system without extensive modification thereof.